全文获取类型
收费全文 | 7259篇 |
免费 | 162篇 |
国内免费 | 10篇 |
专业分类
化学 | 4857篇 |
晶体学 | 76篇 |
力学 | 93篇 |
数学 | 1042篇 |
物理学 | 1363篇 |
出版年
2021年 | 50篇 |
2020年 | 57篇 |
2019年 | 62篇 |
2016年 | 120篇 |
2015年 | 106篇 |
2014年 | 125篇 |
2013年 | 263篇 |
2012年 | 235篇 |
2011年 | 263篇 |
2010年 | 184篇 |
2009年 | 155篇 |
2008年 | 259篇 |
2007年 | 226篇 |
2006年 | 248篇 |
2005年 | 222篇 |
2004年 | 224篇 |
2003年 | 197篇 |
2002年 | 188篇 |
2001年 | 158篇 |
2000年 | 151篇 |
1999年 | 122篇 |
1998年 | 87篇 |
1997年 | 85篇 |
1996年 | 135篇 |
1995年 | 100篇 |
1994年 | 121篇 |
1993年 | 103篇 |
1992年 | 100篇 |
1991年 | 105篇 |
1990年 | 106篇 |
1989年 | 95篇 |
1988年 | 107篇 |
1987年 | 116篇 |
1986年 | 101篇 |
1985年 | 114篇 |
1984年 | 131篇 |
1983年 | 105篇 |
1982年 | 120篇 |
1981年 | 117篇 |
1980年 | 95篇 |
1979年 | 95篇 |
1978年 | 112篇 |
1977年 | 106篇 |
1976年 | 100篇 |
1975年 | 109篇 |
1974年 | 96篇 |
1973年 | 67篇 |
1972年 | 44篇 |
1971年 | 48篇 |
1970年 | 47篇 |
排序方式: 共有7431条查询结果,搜索用时 0 毫秒
1.
2.
3.
F. Meyer 《Fresenius' Journal of Analytical Chemistry》1885,24(1):617
Ohne Zusammenfassung 相似文献
4.
J. R. Lindle W. W. Bewley I. Vurgaftman J. R. Meyer J. L. Johnson M. L. Thomas W. E. Tennant 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):558
A self-referencing, optical modulation technique was used to measure the negative luminescence efficiencies of an array of mid-wave infrared HgCdTe photodiodes with cutoff wavelength 4.6 μm as a function of sample temperature. The internal efficiency at a wavelength of 4 μm was 93% at 295 K, and nearly independent of temperature in the 240–300 K range. This corresponds to an apparent temperature reduction >50 K at room temperature and >30 K at 240 K. Moreover, the reverse-bias saturation current density was only 0.13 A/cm2. The measured transmission and emission spectra were simulated using empirical HgCdTe absorption formulas from the literature. 相似文献
5.
Andrzej Dabrowski Erich Robens Peter Klobes Klaus Meyer Przemyslaw Podkocielny 《Particle & Particle Systems Characterization》2003,20(5):311-322
Since a comprehensive survey published in 1999 [1] much work was done in standardizing measuring methods to characterize the surface geometry of dispersed and/or porous solids and to certify reference materials. The present paper is an extension of a short communication [2]. It gives a survey on existing standards and reports on new drafts and proposals. 相似文献
6.
So-Yon Lim Matt Meyer Richard A Kjonaas Swapan K Ghosh 《Journal of immune based therapies and vaccines》2007,5(1):3-1
This is a correction article. 相似文献
7.
Rolf Dittmann Heinz-Jürgen Feld Wolfgang Samenfink Sigmar Wittig 《Particle & Particle Systems Characterization》1994,11(5):379-384
In utilizing the advantages of extinction measurements in micron and especially submicron particle characterization, the properties of a multiple wavelength extinction technique have been the subject of extended theoretical studies. Furthermore, an experimental set-up was designed which provides high flexibility owing to its modular design. The performance of the technique described is demonstrated by a large variety of applications in aerosol and combustion research and in large-scale industrial systems. It was found to be a reliable tool in characterizing dense particulate systems. 相似文献
8.
Optimal explicit Runge–Kutta methods consider more stages in order to include a particular spectrum in their stability domain
and thus reduce time-step restrictions. This idea, so far used mostly for real-line spectra, is generalized to more general
spectra in the form of a thin region. In thin regions the eigenvalues may extend away from the real axis into the imaginary
plane. We give a direct characterization of optimal stability polynomials containing a maximal thin region and calculate these
polynomials for various cases. Semi-discretizations of hyperbolic–parabolic equations are a relevant application which exhibit
a thin region spectrum. As a model, linear, scalar advection–diffusion is investigated. The second-order-stabilized explicit
Runge–Kutta methods derived from the stability polynomials are applied to advection–diffusion and compressible, viscous fluid
dynamics in numerical experiments. Due to the stabilization the time step can be controlled solely from the hyperbolic CFL
condition even in the presence of viscous fluxes. 相似文献
9.
10.